We will continue to define the components of the immune response associated with immune-mediated suppression of tumor growth in vivo. We plan to exploit the observation that cells generated in vitro which are cytotoxic to syngeneic rat lymphoma cells can confer systemic antitumor immunity on nonimmune recipients. The cellular requirements and the mechanism by which immune cells generate cytotoxic activity and the ability of these cells to confer systemic antitumor immunity on nonimmune recipients will be evaluated. The mechanism by which in vitro generated cytotoxic cells passively confer antitumor immunity on nonimmune recipients and the potential of adoptive immunotherapy using these cells will be assessed. The effect of BCG on the generation of cytotoxic cells is being evaluated. BIBLIOGRAPHIC REFERENCES: Bernstein, I.D., and Wright, P.W.: Generation of cytotoxic lymphocytes in mixed leukocyte culture by rat lymphoid cells. Transplantation 21:173, 1976. Bernstein, I.D., Wright, P.W., and Cohen, E.: Generation of cytotoxic lymphocytes in vitro: Response of immune rat spleen cells to a syngeneic Gross virus-induced lymphoma in mixed lymphocyte-tumor culture. J. Immunol. 116:1367, 1976.